Radioisotopes technetium

The radioisotope technetium-99 is often used as a radiotracer to detect disorders of the body. It has a half-life of 6.01 hours. If a patient received a 25.0-mg dose of this isotope during a medical procedure, how much would remain 48.0 hours after the dose was given ... 

The decay curve for the medically useful radioisotope technetium-99m. Note that the number of radioactive atoms remaining—hence the radioactivity— approaches zero. 

The synthetic radioisotope technetium-99, which decays by beta emission, is the most widely used isotope in nuclear medicine. The following data were collected on a sample of Tc ... 

Many of the uranium fission fragments are radioactive. Of special interest are technetium-99 [14133-76-7] and iodine-129 [15046-84-1] having half-Hves of 2.13 X 10 yr and 1.7 x 10 yr, respectively. Data on all isotopes are found in Reference 6 (see also Radioisotopes). 

Technetium-99m (the m signifies a metastable, or moderately stable, species) is generated in nuclear reactors and shipped to hospitals for use in medical imaging. The radioisotope has a half-life of 6.01 h. If a 165-mg sample of technetium-99m is shipped from a nuclear reactor to a hospital 125 kilometers away in a truck that averages 50.0 kmh. what mass of technetium-99m will remain when it arrives at the hospital ... 

The utilization of radioisotopes in the field of nuclear medicine has been promoted for various purposes. Among them, diagnostic applications have had much success during the past two decades. Technetium-99m, thallium-210 and iodine-123, for example, have been used as radioisotopes for imaging studies. 

Campbell has studied the separation of technetium by extraction with tributyl phosphate from a mixture of fission products cooled for 200 days. Nearly complete separation of pertechnetate is achieved by extraction from 2 N sulfuric acid using a 45 % solution of tributyl phosphate in kerosene. Ruthenium interferes with the separation and is difficult to remove without loss of technetium other radioisotopes can be removed by a cation-exchange process. However, this separation procedure has not been widely applied because of the adverse influence of nitrate. 

In hospitals, radioisotope Mo-99, which decays into technetium-99, is given internally to cancer patients as a radioactive cocktail. Radioactive Tc-99 is absorbed by tissues of cancer patients, and then x-ray-hke radiation is used to produce pictures of the body s internal organs. 

ISOTOPES There are 47 isotopes. None are stable and all are radioactive. Most are produced artificially in cyclotrons (particle accelerators) and nuclear reactors. The atomic mass of its isotopes ranges from Tc-85 to Tc-118. Most of technetium s radioactive isotopes have very short half-lives. The two natural radioisotopes with the longest half-lives—Tc-98 = 4.2x10+ years and Tc-99 = 2.111 xl0+ years—are used to establish technetium s atomic weight. 

Special attention has been paid to Re, since this isotope can readily be obtained from isotope generators which are based on the decay of (physical ti/2 = 69.4 d) in a matrix from which the daughter nuclide Re can readily be separated. This permits continuous availability of the radioisotope at the clinic and allows the preparation of Re-radiopharmaceuticals in a kit procedure as has been established for technetium radiopharmaceuticals. W/ Re generators... 

An allied application of radiolabelled anti-tumour monoclonal antibodies is that of diagnostic imaging (immunoscintigraphy). In this case, the radioisotope employed must be a y-emitter (such that the radioactivity can penetrate outward through the body for detection purposes). Although various radioisotopes of iodine have been evaluated, (technetium) is the one... 

Radioactive labels are -emitters selected on the basis of half-lives, the energies emitted, decay products, ease of labeling, availability and expense. Iodine isotopes 121,123, and 124, Indium 111, and Technetium 99 are the labels most widely used. The short half-lives of these labels (hours to days) means that radioimaging reagents are prepared immediately prior to treatment. Radioimaging of diseased tissue also provides useful information on the design of therapies that localize radioisotopes or toxins at tumor sites for therapy. 

Strickert, R., Friedman, A. M., and Fried, S., "The Sorption of Technetium and Iodine Radioisotopes by Various Minerals," Nuclear Technology, in press (1978). 

A Technetium-99m, a short-lived radioisotope used for brain scans, is obtained by neutron bombardment of molybdenum-99 and then stored in a "molybdenum cow" in the form of Mo042. Small amounts are removed by passing a saline solution through the cylinder. 

The radioisotope most widely used today is technetium-99m, whose short half-life of 6.01 hours minimizes a patient s exposure to harmful effects. Bone scans using Tc-99m, such as that shown in Figure 22.12a, are an important tool in the diagnosis of cancer and other pathological conditions. 

Radiochemical purity determinations consist of separating the different chemical substances containing the radionuclide. The radiochemical purity of labeled pharmaceuticals is typically determined by paper chromatography (paper impregnated with silica gel or silicic acid). The most frequently used radioisotope is technetium-99m obtained by daily elution with saline... 

Short-lived technetium Isotopes, produced as a daughter product of molybdenum radioisotopes or as fission products of U255 were extracted as the tetraphenylarsonlum salt In chloroform together with perrhenate carrier (91,262). 

A radioactive isotope (radioisotope) is an unstable isotope of an element that decays into a more stable isotope of the same element. They are of great use in medicine as tracers (to help monitor particular atoms in chemical and biological reactions) for the purpose of diagnosis (such as imaging) and treatment. Iodine (-131 and -123) and Technetium-99 are used for their short half-lives. 

Technetium-99 (43TC) is a common radioisotope used in nuclear medicine. The rate constant for Tc-99 is 1.16 10-1 h-1. What is the half-life of Tc-99 ... 

Strickert R., Friedman A. M., and Fried S. (1980) The sorption of technetium and iodine radioisotopes by various minerals. Nuclear Technol. 49, 253-266. 

C. Syntheses and Structures of Tetraphenylarsonium Complexes with Counter Anions Containing Technetium Radioisotopes... 

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